Blood pressure in pregnancy-A stress test for hypertension? Five-year, prospective, follow-up of the ROLO study.

Objective: To investigate whether maternal blood pressure (BP) below the diagnostic criteria of hypertensive disorders of pregnancy (HDP) is associated with maternal BP 5 years later.

Design: Prospective, observational study.

Setting: Dublin, Ireland (2007-2011).

Sample: Three hundred twenty-nine women from the ROLO study (Randomized cOntrol trial of LOw glycaemic index diet to prevent the recurrence of macrosomia).

Methods: Maternal BP measurements were taken during pregnancy (13, 28 and 34 weeks' gestation and day 1 postpartum) and at the 5-year follow-up. Systolic BP (SBP) and diastolic BP (DBP) were categorized as normal (SBP < 120 and DBP < 80 mm Hg), elevated (SBP 120-129 and DBP < 80 mm Hg), HTN stage 1 (SBP 130-139 or DBP 80-89 mm Hg) or HTN stage 2 (SBP ≥ 140 or DBP ≥ 90 mm Hg) at each timepoint.

Main Outcome Measures: Maternal blood pressure at the 5-year follow-up.

Results: Women with elevated BP at 28 and 34 weeks' gestation had 2.68 (95% CI: 1.36-5.26) and 2.45-fold (95% CI: 1.22-4.95) increased odds of HTN stage 1 respectively, at the 5-year follow-up, compared to those with normal BP in pregnancy.

Conclusion: Elevated BP at 28 and 34 weeks' gestation was associated with an increased risk of HTN stage 1 at 5 years later. Thus, raised BP, below the diagnostic criteria of HDP, could be flagged for follow-up postpartum.